Device for measuring the vertical force required to release a ski boot from a ski heel clamp

ABSTRACT

A Y-shaped lever arm has a forked forward end adapted to straddle the heel of the boot. A heel lifting strap is connected at its ends to the forked end of the lever arm so that the mid portion of the strap may be inserted under the heel of a boot while the boot is secured to a ski by a conventional type of binding having a releasable heel clamp. At an intermediate position in the length of the lever arm a vertical cup member is mounted between the arms of the fork. In the bottom of the cup is a chamber for hydraulic fluid connected with a maximum reading pressure gauge in the upper part of the cup. The lower end of the cup contains a vertical plunger having fulcrum rollers on its lower end to bear against the top of the ski behind the heel binding. The upper end of the plunger bears against a diaphragm closing the lower side of the fluid chamber whereby a downward force applied to the rear end of the lever arm produces an indication in the pressure gauge of the uplift force applied to the boot heel. The rear end of the lever arm is equipped with a folding handle to provide a compact package when the device is not in use.

United States Patent [191 Frey Aug. 20, 1974 DEVICE FOR MEASURING TIIE VERTICAL FORCE REQUIRED TO RELEASE A SKI BOOT FROM A SKI HEEL CLAMP [76] inventor: Max Frey, 3940 S.W. Altadena Ave., Portland, Oreg. 97201 22 Filed: Mar. 13, 1973 21 Appl. No.: 340,919

Primary Examiner-Charles A. Ruehl' Attorney, Agent, or FirmLee. R. Schermerhorn [57] ABSTRACT A Y-shaped lever arm has a forked forward end adapted to straddle the heel of the boot. A heel lifting strap is connected at its ends to the forked end of the lever arm so that the mid portion of the strap may be inserted under the heel of a boot while the boot is secured to a ski by a conventional type of binding having a releasable heel clamp. At an intermediate position in the length of the lever arm a vertical cup member is mounted between the arms of the fork. In the bottom of the cup is a chamber for hydraulic fluid connected with a maximum reading pressure gauge in the upper part of the cup. The lower end of the cup contains a vertical plunger having fulcrum rollers on its lower end to bear against the top of the ski behind the heel binding. The upper end of the plunger bears against a diaphragm closing the lower side of the fluid chamber whereby a downward force applied to the rear end of the lever arm produces an indication in the pressure gauge of the uplift force applied to the boot heel. The rear end of the lever arm is equipped with a folding handle to provide a compact package when the device is not in use.

7 Claims, 3 Drawing Figures BACKGROUND OF THE INVENTION This invention relates to a portable device for measuring the vertical force required to release a ski boot from a ski heel clamp, for use in adjusting the heel clamp according to the strength and capability of the skier.

Conventional ski bindings for securing a boot on a ski have a toe clamp which is adjusted to release the toe of the boot in response to a predetermined lateral force on the toe, and a heel clamp which is adjusted to release the heel in response to a predetermined upward force. These clamps must be initially adjusted to suit the strength and capability of the skier and may have to be readjusted from time to time in the interest of safety and to allow for changing conditions, such as different types of skiing and increasing strength and skill of the skier.

Portable devices for testing the ski heel clamps have heretofore been less accurate and reliable than desired because of reliance on spring deflection to measure the applied force. Devices having greater accuracy and reliability have been too large and expensive for the personal use of the skier. There is need for an improved small portable device which may be used conveniently by the skier to adjust his bindings from time to time in order to avoid premature release on the one hand or injury from failure to release on the other hand.

Objects of the invention are, therefore, to provide an improved portable device for measuring the uplift force required to release a ski boot from a ski heel clamp and to provide a device of the type described which is highly accurate and reliable and yet of relatively simple and inexpensive construction.

SUMMARY OF THE INVENTION In the present device a Y-shaped lever arm has a forked forward end adapted to straddle the heel of the boot. A heel lifting strap is connected at its ends to the forked end of the lever arm so that the mid portion of the strap may be inserted under the heel of a boot while the boot is secured to a ski by a conventional type of binding having a releasable heel clamp.

At an intermediate position in the length of the lever arm a vertical cup member is mounted between the arms of the fork. In the bottom of the cup is a chamber for hydraulic fluid connected with a maximum reading pressure gauge in the upper part of the cup. The lower end of the cup contains a vertical plunger having fulcrum rollers on its lower end to bear against the top of the skibehind the heel binding. The upper end of the plunger bears against a diaphragm closing the lower side of the fluid chamber whereby a downward force applied to the rear end of the lever arm produces an indication in the pressure gauge of the uplift force applied to the boot heel. The rear end of the lever arm is equipped with a folding handle to provide a compact package when the device is not in use.

The foregoing and other objects and advantages will become apparent and the invention will be better understood with reference to the following description of a preferred embodiment of the invention illustrated on the accompanying drawing. Various changes may be made in the details of construction and arrangement of parts and certain features may be used without others. All such modifications within the scope of the appended claims are included in the invention.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevation view with parts broken away, showing a device embodying the invention;

FIG. 2 is a top plan view with parts broken away; and

FIG. 3 is a view on the line 3-3 in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT The boot B is secured to the ski S by a conventional type of binding having an adjustable toe clamp (not shown) which releases in response to a predetermined force exerted on the boot in a lateral direction and a heel clampC which releases the boot in reponse to a predetermined uplift force. These clamps are adjustable to suit the needs of the skier.

The present device comprises a Y-shaped lever arm 10 having a forked front end formed by a pair of divergent arms 11. The forward ends of the arms 11 support the ends of a strap sling 12 which is adapted to underlie the heel of the boot as shown.

A vertical cup housing 13 is mounted in the fork of the arms 11 at a distance rearward from the heel of the boot by means of rivets 14. Cup 13 has an integral bottom part 15 which forms a guide for a vertical plunger 20. The lower end of plunger 20 is equipped with fulcrum rollers 21 adapted to bear on the top of the ski a short distance behind the heel clamp C.

Plunger 20 is retained in bottom part 15 by a small pin 22 which extends through a large hole 23 in the plunger allowing for vertical movement of the plunger.

The upper end of plunger 20 bears against a diaphragm 24 which closes the lower side of a fluid chamber 25 containing hydraulic fluid. Chamber 25 is formed as a cavity in a block 26 which is secured to part 15 by screws 27. A maximum reading pressure gauge 29 in the upper end of cup member 13 is connected to chamber 25.

In order to provide the necessary leverage for manual operation, the rear end of lever am 10 is preferably extended by a folding handle 30. Handle 30 contains a hollow roll pin 31 on a bolt 34 in the rear ends of fork arms 11 with the front end of the handle being arranged to bear against the underside of a roll pin 32 in arms 11 when the outer end of the lever arm is pressed downward in the direction of arrow 33. This construction allows the handle to pivot on bolt 34 and fold compactly into position 30a when the device is not in use. Bolt 34 and pin 32 hold the rear ends of fork arms 11 in parallel relation so that handle 30 may swing between the arms 11 as shown.

It will be apparent that when the handle 30 is pressed downward, the lever arm 10 fulcrums on rollers 21 and applies an uplift force to the heel of the boot through strap 12. Since the relationship of the downward force exerted on fulcrum rollers 21 to the uplift force applied to strap 12 depends on the leverage geometry, it is necessary to insure that the handle 30 is always grasped at a particular point in its length.

Thus, a collar 35 is affixed to handle 30 to define a hand grip portion 36 extending from the coller to the end of the handle. When the operator grasps the handle 30 inthe hand gripportion 36, the-leverage geometry is fixed. and determined whereby pressure gauge 29 may be calibrated to indicate the values of uplift force applied to strap 12 in terms of pounds or kilograms.

The pressure gauge 29 may be any conventional type of maximum pressure indicating gauge. One suitable form of such gauge has an indicator needle which is advanced over a scale by movement of a fluid pressure responsive needle. When the clamp C releases the boot, the fluid pressure responsive needle immediately returns to zero leaving the maximum indicating needle in its actuated position. After this position is observed, the maximum indicating needle may be returned manually to zero position in preparation for the next test following appropriate adjustment of the clamp C.

Since plunger 20 is not spring actuated it does not forcefully eject the boot from the ski when the clamp C releases. This is an objectionable feature of springtype measuring gauges.

Having now described my invention and in what manner the same may be used, what I claim as new and desire to protect by Letters Patent is:

l. A device for measuring the uplift force required to release a ski boot from a ski heel clamp comprising a lever arm having a forward end equipped with lift means adapted to extend under the heel of a boot secured on a ski by a releasable binding, a housing mounted on said lever arm, a vertical plunger slidable in said housing, fulcrum rollers on the lower end of said plunger adapted to rest on the ski, a hydraulic fluid chamber in said housing, a diaphragm closing the bottom of said chamber and bearing against the upper end 4 of said plunger, and a maximum reading pressure gauge in said housing connected to said chamber.

2. A device as defined in claim 1, said lever arm comprising a Y-shaped member having a pair of arms adapted to straddle the boot, said lift means comprising a sling attached to said pair of arms, and said housing being mounted between said pair of arms.

3. A device as defined in claim 2, including a handle pivotally mounted between said pair of arms on a pin interconnecting said pair of arms, and a second pin interconnecting said pair of arms to form an abutment for limiting the pivotal movement of said handle in a downward direction.

4. A device as defined in claim 1, said housing com prising a cup having a bottom part with a vertical bore for said plunger, said fluid chamber and diaphragm being mounted on said bottom part, and said pressure gauge being mounted on said fluid chamber and disposed in the upper part of said cup.

5. A device as defined in claim 3 including a small horizontal pin in said bottom part intersecting said bore and extending through a large hole in said plunger to retain the plunger and allow vertical movement thereof in said bore.

6. A device as defined in claim 1 including a folding handle arranged to extend the length of the rear end of said lever arm.

7. A device as defined in claim 3, including a collar on said handle to define the limit of a hand grip between said collar and the free end of the handle.

v v v I I- Qg;;g=; UNITED STATES PATENT OFFICE L 4 ERTIFICATE OF CORRECTION 3.830.101- v net-d A i w l v Inventor) MAX FREY It is certified that error appears in the above-identified patent and ghat said Letters Patent are hereby corrected as shown below:

Column 1;, line 20, "claim 3" should read claim h Column h, line 28, "claim 3" should read claim 6 Signed and sealed this 5th day of November 1974.

(SEAL) Attest 2 McCOY M.- GIBSON JR. C. MARSHALL DANN.

Attesting Officer Commissioner of Patents 

1. A device for measuring the uplift force required to release a ski boot from a ski heel clamp comprising a lever arm having a forward end equipped with lift means adapted to extend under the heel of a boot secured on a ski by a releasable binding, a housing mounted on said lever arm, a vertical plunger slidable in said housing, fulcrum rollers on the lower end of said plunger adapted to rest on the ski, a hydraulic fluid chamber in said housing, a diaphragm closing the bottom of said chamber and bearing against the upper end of said plunger, and a maximum reading pressure gauge in said housing connected to said chamber.
 2. A device as defined in claim 1, said lever arm comprising a Y-shaped member having a pair of arms adapted to straddle the boot, said lift means comprising a sling attached to said pair of arms, and said housing being mounted between said pair of arms.
 3. A device as defined in claim 2, including a handle pivotally mounted between said pair of arms on a pin interconnecting said pair of arms, and a second pin interconnecting said pair of arms to form an abutment for limiting the pivotal movement of said handle in a downward direction.
 4. A device as defined in claim 1, said housing comprising a cup having a bottom part with a vertical bore for said plunger, said fluid chamber and diaphragm being mounted on said bottom part, and said pressure gauge being mounted on said fluid chamber and disposed in the upper part of said cup.
 5. A device as defined in claim 3 including a small horizontal pin in said bottom part intersecting said bore and extending through a large hole in said plunger to retain the plunger and allow vertical movement thereof in said bore.
 6. A device as defined in claim 1 including a folding handle arranged to extend the length of the rear end of said lever arm.
 7. A device as defined in claim 3, including a collar on said handle to define the limit of a hand grip between said collar and the free end of the handle. 